• Korea-Australia Rheology Journal
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• v.15 no.4
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• pp.167-171
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• 2003

The backlight unit (BLU) is used as a light source of TFT liquid-crystalline-display (TFT-LCD) module. In this backlight unit, one of important components is the light guide, which is usually made of transparent polymers. Currently, the screen-printing method is mainly used for the light guide as a manufacturing process. However, it has limitation to the flexibility of three-dimensional optical design. In the present paper a new alternative manufacturing method for the light guide with low-cost is proposed. This manufacturing method is named as direct surface forming (DSF), which is very similar to the well-known hot embossing except for partial contact between mold and substrate. The results of this new manufacturing method are presented in terms of processing condition, dimensional accuracy, productivity, etc.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.223-226
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• 2002

To maximize the productivity in machining molds and dies, machine tools should operate at high speeds. However, the productivity of mold manufacturing has not increased significantly because CNC milling machines have massive slides, which do not allow rapid acceleration and deceleration during the frequent starts/stops encountered in machining molds and dies. This paper presents the use of composites for these slides to overcome this limitation. The vertical and horizontal slides of a large CNC machine were constructed by bonding high-modulus carbon-fiber epoxy composite sandwiches to welded steel structures using adhesives. These composite structures reduced the weight of the vertical and horizontal slides by 34% and 26%, respectively, and increased damping by 1.5 to 5.7 times without sacrificing the stiffness. Without much tuning, this machine had a positional accuracy of $\pm5\mu\textrm{m}$ per 300 m of the slide displacement.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.16-22
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• 2011

Recently, the deburring process which is last process of manufacture is one of the important process for complete product. The development of shape guided automatic deburring machine is essential because manual deburring process has very irregular quality and higher error rate as well as consider irregular shape radius. In order to develop of shape guided automatic deburring machine, in this study, we conducted 3D design, assembly, machine simulation and structural analysis using CATIA. Also, we conducted to make automatic deburring machine and conducted a performance test.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.9
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• pp.9-14
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• 2020

In this study, CFX analyses were performed with flow models to minimize the flow resistance due to the windscreen on the front of a car body. The results indicated that the greater the slant angle of the windshield, the greater the maximum pressure area. The lower the slant angle of the windscreen, the smaller the area in which the air collides with the front of the car body and the more smoothly the air moves. The results of this study can be applied to increase fuel economy under driving conditions by changing the slant angle of the vehicle's windscreen.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.593-600
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• 2012

Thixomolding of Mg-alloy is a semi-solid injection molding process utilizing thixotropic phenomenon. Using this process, higher strength, thinner wall section and tighter tolerance without porosity are obtained. It has been applied for production of near-net-shape magnesium component. To design optimal thixomolding process of Mg-alloy part, molding conditions such as slurry temperature, mold temperature and injection time should be determined properly. Selection of these parameters has been dependent upon engineers' experience and intuitiveness. In this paper, to improve mechanical properties of the thixomolded product, optimal selection of process variables such as injection velocity, barrel temperature and die temperature in the process has been studied through microstructural analysis and Taguchi method. Performance of the process is verified through experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.49-53
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• 2008

This study deals a way to reduce the transformer noises. The first step is to identify the source of the transformer noises. The second step is obtaining the vibration characteristics of transformer; its natural frequencies and mode shapes. Based on these information, an method to reduce the vibration of transformer can be found. The cause of transformer noises is mainly due to the magnetostrictive vibration of a core which is made of ferromagnetic substances. It is well known that the magnetostrictive vibration of a core is unavoidable, and a way to reduce the transformer noise by structural design is needed. It requires understanding the vibration characteristics. The natural frequencies and the mode shapes of transformer are analyzed by performing the modal testing.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.8
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• pp.659-663
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• 2014

Manufacturing processes of industrial tire are composed of mixing, extrusion, curing, trimming and inspecting. Among them curing is the most important process in the production of industrial tire. In this study the newly developed spring vent system was designed in order to solve rubber intrusion problem inside spring vent system in the curing process. After the experiment it is concluded that rubber intrusion was caused by angled stem head part. New spring vent system was manufactured and new design of spring vent system is proper to use for industrial tire curing process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.715-718
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• 2002

This paper describes the Boolean and sectioning operations on pseudo-solid models. A pseudo-solid model is defined as a sheet body that looks like a solid model but cannot comprise a solid model due to tolerance. Most of CAD models imported from the other CAD system are pseudo-solid models and have to be repaired for further stolid modeling operations. However, healing a pseudo-solid model is a very tedious and cumbersome process. To solve this problem, we devised and implemented the Boolean and sectioning operations on pseudo-solid models. Using these operations, mold and die design can be performed more efficiently, as healing work is reduced greatly.

• Journal of Welding and Joining
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• v.33 no.4
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• pp.24-29
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• 2015

The current waveform was analysed to monitor the weld quality in real time process. The acquired current waveform was discretely analysed for the top and bottom limits of peaks as well as the pulse frequency measurement. Fast Fourier Transform was implemented in the program to monitor the pulse frequency in real time. The developed algorithm or program was tested for the validation purpose. The cross-section of weld profile was compared to the current waveform profile to correlate the monitored signal and the actual parts. Pulse frequency was also used as auxiliary tool for the quality monitoring. Based on the results, it was possible to evaluate the quality of welding by measure the current waveform profile and frequency measurement.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.7-13
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• 1999

The potential for growth and the future impact of Rapid Prototyping that it will have on the product development cycle are enormous. Since making tools, precedes making parts, Rapid Tooling becomes widely used in automobile, aerospace, electronic, and other industries. In this study, master models formed by Rapid Prototyping of Stereolithography have been applied for vacuum casting to obtain silicone patterns which have transformed into epoxy models. The epoxy models have been measured to check dimension errors, and tested their functions. These checking and measurement have provided information on plastic injection possibilities and data for die design, Temporary die making with the materials of Aluminum/Epoxy and powder injection metal (PIM) has also been discussed in terms of hardness, surface roughness, and SEM microstructures.